Portable burglar alarm

ABSTRACT

A portable burglar alarm having a housing containing a bell and a spring driven motor. The alarm also has an elongated supporting mechanism connected to the housing and operatively coupled to the spring driven motor. The alarm is adapted for leaning the housing against a moveable surface with the elongated supporting mechanism resting on a fixed surface. The alarm is set up in an upright position. Movement of the moveable surface topples the device and when the supporting mechanism no longer supports a substantial portion of the weight of the housing, the spring driven motor becomes operative and sounds the bell.

llnited States Patent [191 Murray 4 1 Nov. 25, 1975 PORTABLE BURG LAR ALARM Inventor: Harry Aloysious Murray, 146 Red Stone Ridge, Delran, NJ. 08075 Filed: Oct. 23, 1974 Appl. No.: 517,080

Primary ExaminerRichard C. Queisser Assistant ExaminerDanie1 M. Yasich Attorney, Agent, or Firm-Joseph Tripoli 57 ABSTRACT A portable burglar alarm having a housing containing a bell and a spring driven motor. The alarm also has an elongated supporting mechanism connected to the housing and operatively coupled to the spring driven motor. The alarm is adapted for leaning the housing against a moveable surface with the elongated supporting mechanism resting on a fixed surface. The alarm is set up in an upright position. Movement of the moveable surface topples the device and when the supporting mechanism no longer supports a substantial portion of the weight of the housing, the spring driven motor becomes operativeand sounds the bell.

9 Claims, 3 Drawing Figures PGRTABLE BURGLAR ALARM The present invention relates generally to burglar alarms and more specifically to portable burglar alarms.

In the prior art there are several types of portable burglar alarms. Examples of prior art portable burglar alarms are shown in US. Pat. Nos. 376,909; 857,351; and 1,685,4l6. In each of these examples of prior art, the burglar alarm takes the form of a wedge-like device which is designed to be placed directly behind a door. When the door starts to swing open it gets wedged by the device and a bell is sounded by virtue of a spring motor which is activated by the force of the door against the device. The devices shown in US. Pat. Nos. 857,351 and 1,685,416 are also shown as being adaptable for use in wedging or jamming a window as a result of an attempted unauthorized opening of the window.

Although the prior art devices mentioned above are useful for sounding an alarm as a result of the unauthorized opening of conventional doors and windows, these devices are not appropriate for sounding an alarm when certain modern type doors and windows are opened. More specifically, these devices are not useful with respect to the unauthorized opening of laterally sliding doors and windows and certain types of casement windows. Many modern homes and many hotels and motels now utilize sliding glass doors and windows. These types of doors and windows are a ready means of unauthorized entrance into a room.

A portable burglar alarm should then have the capability of sounding an alarm upon the unauthorized opening of any type of door or window which the user desires to alarm. The present invention provides a portable burglar alarm which does not require electrical wiring, is easily set up by the user, is not complex in construction and is useful for alarming virtually any type of door or window.

In accordance with the present invention there is provided a portable burglar alarm having a housing within which is located a bell and a spring driven alarm means for sounding the bell. An elongated supporting leg means which is connected to the housing and operatively coupled to the spring driven alarm means is also provided. The burglar alarm is adapted for having the housing contact a moveable surface, such as a door, while the supporting leg means rests against a fixed surface, such as a floor. The supporting leg means supports a substantial portion of the weight of the housing when the burglar alarm is in this upright set up position. The supporting leg means becomes disengaged from the alarm means such that the bell is sounded when movement of the moveable surface causes dislocation of the supporting leg means from the fixed surface.

IN THE FIGURES FIG. 11 is a sketch of one embodiment of the present invention positioned to alarm a door;

FIG. 2 is a cutaway drawing showing the alarm mech anism of the alarm shown in FIG. I; and

FIG. 3 is a perspective view of the alarm of FIG. 2 showing how the device can be used to alarm a variety of moveable surfaces.

Referring now to FIG. 1, the embodiment of a portable burglar alarm in accordance with the present invention is shown having a substantially enclosed housing 10, a supporting leg 12 and a moveable arm 14 located within the supporting leg 12. In. addition, the moveable arm 14 is shown having a foot member 16 resting against afixed surface 18 such as a floor. The housing 10 is set up to lean against the moveable surface 20, such as a door, which is desired to be alarmed. There is also shown in FIG. 1 a key 22 which is used to wind up the coiled spring of the spring driven motor located within the housing 10.

Housing 10 is preferably formed from a high impact plastic material such that the housing 10 will withstand the impact sustained from falling over onto the floor 18 when the door 20 moves and dislocates the unit from its set up position. They key 22 is shown inserted in the housing 10. In some embodiments such as the one shown in FIG. 1, the key 22 is designed to wind the spring motor located within the housing 10 and is then removed. In other embodiments it may be desired to design the key 22 such that it is screwed into the spring driven motor to prevent possible misplacement of the key 22.

The unit shown in FIG. 1 is designed to have a housing 10 which has, an upper portion which is substantially larger in at least one plane, the horizontal plane, than the lower portion thereof in a corresponding plane nearthe area where the supporting leg 12 is connected to the housing 10. In addition the device shown in FIG. 1 is preferably designed to have its center of gravity fairly high with respect to the midpoint of the height of the device from the top of the housing 10 to the foot member 16. These features are preferred so that the device" as a whole is fairly unstable when in its set up position with most of the weight of the device being supported by the moveable arm. 14. It is desired to have the device unstable so that even small movements of door20 will knock the device over causing the alarm to sound.

Referring now to FIG. 2 the details of the alarm mechanism are shown. The cutaway drawing of FIG. 2 showns the bells 30 and 32 secured within the housing 10 by screws 34 and 36 respectively. In close physical proximity to bells 30 and 32 is clapper 38. Clapper 38 is operatively coupled to a spring driven motor device 40 having opening 42 adapted to receive the key 22 for winding up the coiled spring found inside of the spring motor 40. Details of the elements comprising the spring motor 40, the coupling arrangement to the clapper 38 and the means to release the potential energy of the coiled spring within the motor 40 are known in the prior art and may be found in US. Pat. Nos. 376,909; 857,351; and 1,685,416.

FIG. 2 also shows moveable arm 14 having a generally cylindrical form located within and coaxial with the cylindrical supporting leg 12. The moveable arm 14 has a smaller diameter portion 44 on one end. Arm 14 also has first and second protuberances 46 and 48 on the outer surface thereof at a distance from the other end. Protuberances 46 and 48 are designed to act as stops for the travel of moveable arm 14 in one direction. Within the area defined by the inner surface of supporting leg 12 and the narrow diameter portion of moveable arm 14 is located a helical spring 50. I-Ielical spring 50 is designed to force the moveable arm 14 down and away from engagement with spring motor 40. In FIG. 2 spring 50 is shown in its uncompressed state. Thisis the state which spring 50 assumes when the alarm device is not in its set up position, the set up position being that shown in FIG. 1

Attached to the other end of moveable arm 14 is a foot member 16. Foot member 16 has associated therewith a pivot 52 which is inserted into a hollow lower section of moveable arm 14. Pivot 52 is provided so that the foot member 16 may lie flat on the fixed surface such as a floor or the top surface of the lower half of a window even though the upper portion of the housing is leaning against the moveable surface whereby the device as a whole is at an angle with respect to the vertical direction.

Although. the device as a whole is designed to be somewhat unstable so as to readily have the housing 10 fall over from slight movements of the surface upon which it is leaning, the device should have enough stability so that the user may easily prop up the device against the surface to be alarmed.

The device shown in FIG. 2 is set up as follows. First the key 22 is inserted in the opening 42 of spring motor 40 and the coiled spring contained therein is wound. The device is then placed up against the surface to be alarmed with the foot member 16 resting on a fixed surface. The weight of the housing 10 and the elements contained therein compresses spring 50 and the weight of the device is such that spring 50 remains compressed while the device is in the leaning position. In this position the upper end 44 of moveable arm 14 is urged against and engages the spring motor mechanism 40 such that the motor 40 is prevented from driving the clapper 38 and sounding the bells and 32. In an arrangement such as the one referenced in US. Pat. No. 857,351 the end 44 of moveable arm 14 would be coupled to the arm 13 of the referenced patent such that the spring motor 40 would not cause the bells 30 and 32 to be sounded when the alarm is in the set up position. In an arrangement such as the one referenced in US. Pat. No. 1,685,416 the end 44 of moveable arm 14 would be coupled to hammer 47 of the referenced patent such that the bells 30 and 32 would be prevented from sounding by preventing motion of the clapper 38 when the alarm is in the set up or leaning position.

When an unauthorized attempt is made to open the door against which the device is leaning, the device will topple over. As the device topples over and moveable arm 14 no longer bears a substantial portion of the weight of the housing 10, the spring 50 expands from its compressed condition thereby driving moveable arm 14 down and away such that end 44 of arm 14 becomes disengaged from the spring motor 40. Arm 14 is moved by the force of the spring 50 until its movement is stopped by the protuberances 48 and 46 coming into contact with the lower end of supporting leg 12. When end 44 of arm 14 becomes disengaged from motor 40, the stored energy of the motor is released which drives the clapper 38 causing the bells 30 and 32 to be sounded.

Referring now to FIG. 3 a portable burglar alarm in accordance with the present invention is shown in its set up position. The device shown in H0. 3 has two openings 60 and 62 in the housing 10 in physical proximity to bells 30 and 32 respectively. The function of openings 60 and 62 is to allow the escape of the sound waves created when clapper 38 strikes bells 30 and 32. The housing 10 along with openings 60 and 62 is designed to act as a sounding board so that upon the sounding of the bells 30 and 32 a loud resonant sound will be emitted from the device.

FIG. 3 is further illustrative of the use of the portable alarm device with a variety of moveable surfaces depicted generally as 64. If surface 64 is part of a conventional door, then the direction of movement upon opening is that shown by the arrow A. Clearly such movement will topple the device and the alarm will be sounded. If the surface 64 is part of a sliding door the direction of movement upon opening is that shown by the arrow B. Again, due to the construction of the device, it will topple over and the alarm will be sounded. If the surface 64 is part of a window then the direction of movement upon opening may be that shownby the arrow C. In this case the supporting leg 12 and the moveable arm 14 will be set up fairly close to the surface 64 so that even this sliding motion will be sufficient to topple the device and thus cause the alarm to be sounded.

Thus, the present invention provides a portable burglar alarm which is economical to construct and is useable to alarm a plurality of surfaces the unauthorized movement of which will be indicated by the sounding of the alarm.

What is claimed is:

l. A portable burglar alarm for detecting the unauthorized movement of a moveable surface, said burglar alarm comprising:

a housing having substantial weight;

a bell located within said housing;

a spring driven motor located within said housing;

a clapper connected to said spring driven motor for striking said bell when driven by said spring driven motor;

a supporting leg Connected to said housing;

a moveable arm located within said supporting leg, one end of said moveable arm engaging said spring driven motor for preventing operation thereof when said moveable arm supports a substantial portion of the weight of said housing; and v a spring means located between said one end of said moveable arm and said supporting leg and in contact with said moveable arm for disengaging said moveable arm from said spring driven motor for allowing operation thereof when said moveable arm is not supporting a substantial portion of the weight of said housing;

said burglar alarm being positioned such that said housing contacts said moveable surface and the other end of said moveable arm rests upon a fixed surface, said bell being sounded when movement of said moveable surface relative to said fixed surface causes dislocation of said other end of said moveable arm such that said moveable arm no longer supports a substantial portion of the weight of said housing.

2. The burglar alarm according to claim 1 wherein said housing has an opening in proximity to the location of said bell.

3. The burglar alarm according to claim 2 further comprising a foot member connected to said other end of said moveable arm such that said foot member lies flat of said fixed surface when said housing is in contact with said moveable surface.

4. A portable burglar alarm for detecting the unauthorized movement of a moveable surface, said burglar alarm comprising:

a substantially weighted enclosed housing, said housing having an upper and a lower portion;

at least one bell located within said housing;

a key wound spring driven motor located within said housing;

a clapper connected to said spring driven motor for striking said at least one bell when driven by said spring driven motor;

an elongated supporting leg connected to said lower portion of said housing;

a moveable arm located within said supporting leg, one end of said moveable arm engaging said spring driven motor for preventing operation thereof when said moveable arm supports a substantial portion of the weight of said housing;

a helical spring located between said one end of said moveable arm and said supporting leg for disengaging said moveable arm from said spring driven motor for allowing operation thereof when said moveable arm is not supporting a substantial portion of the weight of said housing; and A means located within said supporting leg for restricting the travel distance of said moveable arm within said supporting leg;

said burglar alarm being positioned such that said housing contacts said moveable surface and the other end of said moveable arm rests upon a fixed surface, said at least one bell being sounded when movement of said moveable surface relative to said fixed surface causes dislocation of said other end of said moveable arm such that said moveable arm no longer supports a substantial portion of the weight of said housing.

5. The burglar alarm according to claim 4 wherein first and second bells are located within said housing in proximity to said clapper.

6. The burglar alarm according to claim 5 wherein said housing has first and second openings in proximity to said first and second bells respectively.

7. The burglar alarm according to claim 6 wherein the upper portion of said housing has a greater crosssectional area in a horizontal plane than the lower portion of said housing in a corresponding parallel horizontal plane.

8. The burglar alarm according to claim 7 further comprising a foot member connected to said other end of said moveable arm such that said foot member lies flat on said fixed surface when said housing is in contact with said moveable surface.

9. The burglar alarm according to claim 8 wherein said moveable arm comprises an upper and a lower portion, the upper portion of said moveable arm having a smaller cross-sectional area than the lower portion of 

1. A portable burglar alarm for detecting the unauthorized movement of a moveable surface, said burglar alarm comprising: a housing having substantial weight; a bell located within said housing; a spring driven motor located within said housing; a clapper connected to said spring driven motor for striking said bell when driven by said spring driven motor; a supporting leg connected to said housing; a moveable arm located within said supporting leg, one end of said moveable arm engaging said spring driven motor for preventing operation thereof when said moveable arm supports a substantial portion of the weight of said housing; and a spring means located between said one end of said moveable arm and said supporting leg and in contact with said moveable arm for disengaging said moveable arm from said spring driven motor for allowing operation thereof when said moveable arm is not supporting a substantial portion of the weight of said housing; said burglar alarm being positioned such that said housing contacts said moveable surface and the other end of said moveable arm rests upon a fixed surface, said bell being sounded when movement of said moveable surface relative to said fixed surface causes dislocation of said other end of said moveable arm such that said moveable arm no longer supports a substantial portion of the weight of said housing.
 2. The burglar alarm according to claim 1 wherein said housing has an opening in proximity to the location of said bell.
 3. The burglar alarm according to claim 2 further comprising a foot member connected to said other end of said moveable arm such that said foot member lies flat of said fixed surface when said housing is in contact with said moveable surface.
 4. A portable burglar alarm for detecting the unauthorized movement of a moveable surface, said burglar alarm comprising: a substantially weighted enclosed housing, said housing having an upper and a lower portion; at least one bell located within said housing; a key wound spring driven motor located within said housing; a clapper connected to said spring driven motor for striking said at least one bell when driven by said spring driven motor; an elongated supporting leg connected to said lower portion of said housing; a moveable arm located within said supporting leg, one end of said moveable arm engaging said spring driven motor for preventing operation thereof when said moveable arm supports a substantial portion of the weight of said housing; a helical spring located between said one end of said moveable arm and said supporting leg for disengaging said moveable arm from said spring driven motor for allowing operation thereof when said moveable arm is not supporting a substantial portion of the weight of said housing; and means located within said supporting leg for restricting the travel distance of said moveable arm within said supporting leg; said burglar alarm being positioned such that said housing contacts said moveable surface and the other end of said moveable arm rests upon a fixed surface, said at least one bell being sounded when movement of said moveable surface relative to said fixed surface causes dislocation of said other end of said moveable arm such that said moveable arm no longer supports a substantial portion of the weight of said housing.
 5. The burglar alarm according to claim 4 wherein first and second bells are located within said housing in proximity to said clapper.
 6. The burGlar alarm according to claim 5 wherein said housing has first and second openings in proximity to said first and second bells respectively.
 7. The burglar alarm according to claim 6 wherein the upper portion of said housing has a greater cross-sectional area in a horizontal plane than the lower portion of said housing in a corresponding parallel horizontal plane.
 8. The burglar alarm according to claim 7 further comprising a foot member connected to said other end of said moveable arm such that said foot member lies flat on said fixed surface when said housing is in contact with said moveable surface.
 9. The burglar alarm according to claim 8 wherein said moveable arm comprises an upper and a lower portion, the upper portion of said moveable arm having a smaller cross-sectional area than the lower portion of said moveable arm. 